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/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#include <linux/kernel.h>
#include <linux/string.h>
asmlinkage void chacha20_ard_block_xor_neon(u32 *state, u8 *dst, const u8 *src);
asmlinkage void chacha20_ard_4block_xor_neon(u32 *state, u8 *dst, const u8 *src);
enum {
CHACHA20_IV_SIZE = 16,
CHACHA20_KEY_SIZE = 32,
CHACHA20_BLOCK_SIZE = 64,
CHACHA20_BLOCK_WORDS = CHACHA20_BLOCK_SIZE / sizeof(u32)
};
#define EXPAND_32_BYTE_K 0x61707865U, 0x3320646eU, 0x79622d32U, 0x6b206574U
void chacha20_ard_neon(u8 *dst, const u8 *src, u32 len, const u32 key[8], const u32 counter[4])
{
u32 state[] = {
EXPAND_32_BYTE_K,
key[0], key[1], key[2], key[3],
key[4], key[5], key[6], key[7],
counter[0], counter[1], counter[2], counter[3]
};
u8 buf[CHACHA20_BLOCK_SIZE];
unsigned int bytes = len;
while (bytes >= CHACHA20_BLOCK_SIZE * 4) {
chacha20_ard_4block_xor_neon(state, dst, src);
bytes -= CHACHA20_BLOCK_SIZE * 4;
src += CHACHA20_BLOCK_SIZE * 4;
dst += CHACHA20_BLOCK_SIZE * 4;
state[12] += 4;
}
while (bytes >= CHACHA20_BLOCK_SIZE) {
chacha20_ard_block_xor_neon(state, dst, src);
bytes -= CHACHA20_BLOCK_SIZE;
src += CHACHA20_BLOCK_SIZE;
dst += CHACHA20_BLOCK_SIZE;
state[12]++;
}
if (bytes) {
memcpy(buf, src, bytes);
chacha20_ard_block_xor_neon(state, buf, buf);
memcpy(dst, buf, bytes);
}
}
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